Insecticide



PatentedJan. 30, '19'45 UNITED ST TES PATE N ori-"ica ascsssr msnc'rrcnm' vEdward Harvill, Yonkers, N. Y., assignor to Boyce Thompson Institute for Plant Research, Inc.

a corporation of New York No Drawing." Application May 12, 1942, Serial No. 442,693

4 Claims. (Cl. 167-22).

This invention relates .to insecticides and more particularly to insecticidal spray preparations or compositions particularly adapted for combating flies, mosquitoes, moths, roaches, and similar insects. This invention provides an improvedinsecticide or insecticidal composition comprising as a toxicant an organic thiocyanogen compound, which may [be used either alone, or with an extract of a plant product, such as pyrethrum, in

. a mineral oil base or petroleum distillate for. particular use as sprays and the like.

Pyrethrumextracts are widely used for the control of household insect pests and are generally employed in petroleum distillate sprays.

Sprays containing pyrethrum extracts have a rapid paralyzing action on flies but give a relatively low kill as compared to the initial knockdown. It has been generally known that organic thiocyanogen compounds have insecticidal properties to a greater or lesser extent. Despite this knowledge, very few organic thiocyanogen compounds have been used in insecticidal compositions because of the fact that they either must be used in high concentrations, have unpleasant and annoying odors, or are toxicto warm-blooded animals in the concentrations in which they are used or have an irritating efiect.

I have found that organic thiocyanogen compounds of substituted succinic acids are extremely effective as insecticides when used either alone, or in insecticidal preparations or com-positions with a plant extract of pyrethrum, and especially I when used in petroleum distillate sprays. These thiocyanogen compounds which I have discovered as toxicants in insecticides are remarkable in that they may be used in very low concentrations, for example, in concentrations as low as'0.10 per cent by volume. The compounds of the invention are, for the most part, colorless without objectionable odor or irritating or toxic effects, espe-. cially to humans and warm-blooded animals.

They do not cause irritation and dermatitis upon contact with living-animal tissue or skin. Because of their extreme toxicityto insects and their relative harmlessness to animals,,the compounds are well adapted for insecticidal purposes.

The substituted thiocyanogen 'succiiiic acids I have found eflective -as an' insecticide for the purposes of the invention have the following basic rormula:

' cocoa.

H ER] R,- -cooc,Hi-

vention wherein R1 represents hydrogen or an alkyl radical, as for example methyl, ethyl, propyl, or 'butyl, etc.., and where R2 represents a thiocyanoethyl, thiocyanopropyl, or thiocyanohexyl radical.

The following formulae illustrate the aforementioned basic form'uia having various R1 and R2 substitutions forming compounds of the in- Ethyl-alpha-carboethomy-alpha-(gamma-thiccyano propyl) -b'eta-butyl succinate OOCsHu The above compounds may be prepared, ior example by reacting ethyl sodio malonate with an aliphatic alpha halogen ester to give an alpha beta substituted succinic ester. The ethyl sodio succinate is then reacted with a polymethylene halide to give an alpha carlboethoxy, alpha halogenalkyl, beta alkyl succinic ester. This compound is then refluxed with potassium thiocyanate to yield the P und. 2

Various insecticidal spray compositions of the invention may be prepared, for example, by dissolving a compound of the kind described above in a mineral oil base such as odorless kerosene,

naphtha, etc. In addition to petroleum distillate, a

a secondary organic solvent such as ethyl alcohol, acetone, ethylene glycolmonoethyl ether and the like may be used to bring"about solution of the thiocyanogen' succinic compounds in'fiaetroleum distillates inthe case oi those compounds whose desired thioeyanogen com- 2- (assess? acid. The aforementioned secondary organic is solvents meet the requirements with respect to z the compounds of the invention, are non-reactive with pyrethrum and are non-injurious to the skin and general health of humans. The compounds of the invention may be used to fortify liquid extracts of pyrethrum, and to this end, I may incorporate a compound of. the invention in an organic solution of one or these materials either directly or in the form of a solution of a secondary organic solvent. 16.

The following examples illustrate the eflectiveness of various insecticidal compositions of the invention. The eflectiveness oi the compositions was determined by the standard Feet-Grady method with five-day-old flies as described at pages 92 to'98 of "Pyrethrum Flowers by C. B. Gnadinger, 1936 edition. The oflicial test insecticide (0..T. I.) which served as the standard of comparison contained 0.10 percent of pyrethrumfl in the same mineral oil base as the other compositions.

Cone. Per

of .Per;

pymthcent Per Compound mm knocka m (per z g I. g

vol.) #3 min.)

No.1 0.50 as: 00.0 1 40.1 AA

. 0.50 0-05 mo 9&1 31.? AA 0.30 0.03 100 sec 41.1 AA 0. 20 0. 02 99. 4 41. s 41. 1 A o. 10 .0. 0a 100 y 43. 4 41. 7' :s

No. 11---- 1.0 0.05 e 100 93.3 ass AA 0.25 0.05 100 64.3 4.8 4 AA No.-IlI.--. 0.00 I 0.05 100 02.2 43.8 All The first example illustrates the effectiveness of ethyl alp -carboethorzy-alpha.-(gamma-thiccyano propy )-beta-methyl succinate when used as a spray containing no other toxicant.

. compound having the formula Iclaim: I 1. An insecticidal composition comprising a COOCSHI.

11- -n, n.- -oooo,ni

wherein R1 ,represents a member of the group, consisting of hydrogen, methyl, ethyl, propyl and g butyl, and )3: represents a member of the group consisting of beta thiocya'noethyl, gamma thiocyanopropyl, and '6-thiocyanohexyl dissolved in an organic spray liquid.

2. An insecticidal. composition comprising a compound having the formula I COOCQH! n- -n. R:- -coo oini.

oocim wherein R1 represents a member of the -group consisting of hydrogen, methyl, ethyl, propyl and butyl, and R2 represents a member of the group consisting oi beta thiocyan'oethyl, gamma thiocyanopropyl; and fi-thiocyanohexyl and an'extract of pyrethrum. 3. An insecticidal. composition eomprisingran extract of pyrethnun in a mineral oil base, a

coooim .whereinjti represents a member of the group consisting of hydrogen, methyl, ethyl, propyl'and butyl, R2 represents a member of the group consisting of beta thiocyanoethyl, gamma thiocyanopropyl and S-thi'ocy'anohexyl, and asecondsry organic solvent for the compound.

4. An insecticidal preparation according to claim 3 which comprises as a. secondary organic solvent a compound of the group consistlng'ot ethyl alcohol, acetone and ethylene glycolmonoethyl ether. EDWARD HARVILL. 

